A South Carolina husband and wife suspected in the mysterious December disappearance of a cosmetology student now face kidnapping charges.

Sidney and Tammy Moorer were charged with kidnapping on Sunday, according to the Horry County Sheriff’s Office. No bail has been set.

The couple was arrested two days earlier on indecent exposure and obstructing justice charges in the Dec. 18 disappearance of Heather Elvis, 20, who vanished after a date. There’s no word as to what triggered the additional charges.

Elvis’ car was found abandoned at a local boat landing building. Police believe she drove there willingly but have no idea why.

Heather’s parents, Terry and Debbie Elvis, have had difficulty comprehending their daughter’s disappearance.

“Her car was parked where it shouldn’t be, she was nowhere to be found, it was locked and no one was answering her phone,” Terry Elvis said. “Of course, we wanted to pull our hair out.”

After his daughter went missing, Terry Elvis checked Heather’s cell phone records. One number appeared multiple times before her disappearance – Sidney Moorer’s number, Elvis said. Moorer and Heather Elvis may have had a romantic relationship, according to investigators.